The present invention relates to closures for fastening adjacent portions of materials or components together. The closures are useful as fastening system closures for disposable diapers.
Diapers of this general type are widely used. A typical diaper construction comprises an absorbent pad or batt or the like enclosed in an outer plastic shell or a non-woven backsheet that is non-woven fabric laminated with a water impermeable layer such as a polyethylene film. A water permeable inner shell or liner is also provided to promote separation of fluid from the user.
The fastener tape system generally includes adhesive tabs fastened to one end of the diaper assembly construction at each lateral side of the diaper in a permanent xe2x80x9cfactory jointxe2x80x9d by the diaper manufacturer using adhesives or other techniques. The tabs have a face coated with pressure-sensitive adhesive. The tabs are releasably attachable to the other end of the diaper at each lateral side in a xe2x80x9cuser jointxe2x80x9d. The attachment is releasable both to allow permanent removal of the diaper and to allow unfastening to inspect the diaper followed by refastening if indicated.
The user joint may be formed by direct connection of the tab to the diaper outer surface whether the latter is formed of a plastic film or a non-woven backsheet. In the case of plastic film shells, it is typical to provide a xe2x80x9clanding zone or memberxe2x80x9d formed of reinforcing tape or the like for receiving the end of the tab to form the user joint. The landing zone may provide a plastic surface or a non-woven surface and may comprise a knit type fabric landing pad.
The fastener tape system may rely solely upon pressure-sensitive adhesive in the formation of the user joint as shown in U.S. Pat. Nos. 4,795,456, 4,710,190, 4,020,842 and 3,833,456. The use of combined adhesive and mechanical fastener systems is shown in U.S. Pat. Nos. 5,019,065, 5,053,028 and 4,869,724. The teachings of all of these patents being incorporated herein by reference.
The use of extensible or stretchable tabs to promote user comfort through better fit and more secure mounting is also known in the art. The tabs operate as extensible diaper side waistbands. Examples of such diaper fastening systems are disclosed in U.S. Pat. Nos. 4,795,456, 4,066,081, 4,051,853 and 3,800,796. The teachings of these patents being incorporated herein by reference.
Related art includes U.S. Pat. Nos. 4,465,717, 4,662,875, 5,051,259, 5,106,384, 5,133,707, 5,531,731, 5,591,521 and European Publication No. 0 191 355.
The present invention has a number of different aspects relating to improvements in diaper tab fastening systems. These improvements may be used alone or in combination in a fastener system. The fastener system may include an extensible or substantially nonextensible element or tab member.
In a first aspect, the fastening system includes overlying or spatially combined adhesive and mechanical fastening attachments in a tab having an efficient Z-fold configuration. Upon deployment of such tab arrangement to close the diaper, the adhesive provides immediate tack strength and the mechanical attachment provides improved shear strength. The mechanical and adhesive attachments each contribute to the total integrity or strength of the diaper closure or user joint, and neither has to be fully effective to provide the required total closure strength.
In a second aspect, the fastening system has a combined adhesive closure system including both adhesive and cohesive elastomers to effect closure. In this manner, the aggressiveness of adhesives is attained as well as the contaminate resistance of cohesives.
In a third aspect, the fastening system includes a mechanical fastening system having mechanically engaging elements adapted to be received in contoured or obliquely extending apertures in the tab. The mechanical engaging elements have shaped base portions extending to head portions for interengagment within the apertures.
In a fourth aspect, the fastening system includes a mechanical fastening system having an open mesh tab adapted to receive a plurality of mechanical engaging elements. The apertures and mechanical engaging elements are sized and arranged to provide engagement of a plurality of elements in each of the apertures.
In a fifth aspect, the fastening system includes a color indication of proper adhesive engagement of the tab and landing members.